Description:
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Numeric Id keys for stdObj are lost after serializing and 
unseriliazing 

Reproduce code:
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$test = new stdClass();
				$Id = 12;
				$test->$Id = new stdClass();
				$test->$Id->value = 12;
				$Id = '23';
				$test->$Id = new stdClass();
				$test->$Id->value = '23';
				var_dump($test);
				$ser = serialize($test);
				$unser = unserialize($ser);
				echo '<hr />';
				var_dump($unser);
				die('die');

Expected result:
----------------
I would expect both dumps to be the same and the numeric Id keys be 
there after serializing

Actual result:
--------------
After serializing and Unserializing the numeric Id keys are lost